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Int J Mol Epidemiol Genet 2011;2(4):403-408

Original Article
Molecular epidemiology of β-thalassemia in Pakistan: far reaching implications

Saqib H Ansari, Tahir S Shamsi, Mushtaq Ashraf, Muneera Bohray, Tasneem Farzana, Mohammed Tahir Khan, Kousar
Perveen, Sajida Erum, Iqra Ansari, Muhammad Nadeem, Masood Ahmed, Faizan Raza

Department of Pediatric Hematology & Molecular Medicine, National Institute of Blood Diseases, Karachi, Pakistan

Received November 12, 2011; accepted November 21, 2011; Epub November 28, 2011; Published December 15, 2011

Abstract: β-thalassaemia, an autosomal recessive hemoglobinopathy, is one of the commonest genetically transmitted
disorders throughout the world. Collective measures including carrier identification, genetic counseling and prenatal diagnosis
are required for preventing β-thalassemia. To achieve this objective, Identification of the spectrum of genetic mutations,
especially for various ethnic backgrounds in Pakistan is necessary. Therefore, we designed a cross sectional prospective
study to identify the frequency of various gene mutations in different ethnic groups of Pakistan. Over a 5-year period, DNA from
648 blood samples [including specimens of chorionic villus sampling (CVS)] were analyzed for the twelve most common β-
thalassemia mutations found in the Pakistani population by a Multiplex amplification refractory mutation system (ARMS). The
most common mutation identified was Intervening Sequence 1-5 (IVS 1-5 (G-C)); accounting for 40.89% mutated alleles, and
was represented in all ethnic groups. 15.7 % of the β-thalassemia alleles were found to have Frameshift 8-9 (Fr 8-9) as the
second most common mutation Other common genetic defects responsible for β-thalassemia: IVS 1-1 (G-T) was found in
8.17%, Codon-30 (Cd-30 (G-C)) 8.02%, Codon-5(Cd-5 (-CT)) contributed 2.16% and Deletion 619 base pair (Del 619bp)
affected 11.11% were found in Pakistan. This large study adds to the pre-existing data in Pakistan. Knowledge of the
predominant mutation in a given ethnic group will not only help in developing a short panel of (population-specific) primers of
mutations thereby providing a cost-effective method for prenatal diagnosis and also help the clinicians to counsel regarding
blood transfusion regimen/ pregnancy termination. (IJMEG1101003).

Keywords: β-thalassemia, genetic mutations, molecular epidemiology, Pakistan

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Address all correspondence to:
Dr. Saqib Hussain Ansari
Paediatric Haematologist
National Institute of Blood Diseases
ST 2/A, Block 17, Gulshan-e-Iqbal, KDA Scheme 24
Karachi, Pakistan.
Tel: 0092213-4821502-3; Fax: 0092213-4821504
E-mail: muddasirsaqib@yahoo.com